In a dramatic reversal, President Barack Obama on Friday scrubbed a clean-air regulation that aimed to reduce health-threatening smog, yielding to bitterly protesting businesses and congressional Republicans who complained the rule would kill jobs in America’s ailing economy.

Withdrawal of the proposed regulation marked the latest in a string of retreats by the president in the face of GOP opposition, and it drew quick criticism from liberals. Environmentalists, a key Obama constituency, accused him of caving to corporate polluters, and the American Lung Association threatened to restart the legal action it had begun against rules proposed by President George W. Bush.

The White House has been under heavy pressure from GOP lawmakers and major industries, which have slammed the stricter standard as an unnecessary jobs killer. The Environmental Protection Agency, whose scientific advisers favored the tighter limits, had predicted the proposed change would cost up to $90 billion a year, making it one of the most expensive environmental regulations ever imposed in the U.S.

However, the Clean Air Act bars the EPA from considering the costs of complying when setting public health standards.

Obama said his decision was made in part to reduce regulatory burdens and uncertainty at a time of rampant questions about the strength of the U.S. economy.

Underscoring the economic concerns: a new report Friday that showed the economy essentially adding no jobs in August and the unemployment rate stubbornly stuck at 9.1 percent.

The regulation would have reduced concentrations of ground-level ozone, the main ingredient in smog, a powerful lung irritant that can cause asthma and other lung ailments. Smog is created when emissions from cars, power and chemical plants, refineries and other factories mix in sunlight and heat.

Republican lawmakers, already emboldened by Obama’s concessions on extending Bush-era tax cuts and his agreement to more than $1 trillion in spending reductions as the price for raising the nation’s debt ceiling, had pledged to try to block the stricter smog standards as well as other EPA regulations when they returned to Washington after Labor Day.

A spokesman for House Speaker John Boehner, R-Ohio, had muted praise for the White House Friday, saying that withdrawal of the smog regulation was a good first step toward removing obstacles that are blocking business growth.

“But it is only the tip of the iceberg when it comes to stopping Washington Democrats’ agenda of tax hikes, more government ‘stimulus’ spending and increased regulations, which are all making it harder to create more American jobs,” said Boehner spokesman Michael Steel.